1. Field of the Invention
The invention relates to an electric connector, and further to a detection terminal included in the electric connector for detecting whether the electric connector is electrically connected with a second electric connector.
2. Description of the Related Art
It is important for an electric connector defined with a male connector and a female connector to ensure that male and female connectors are surely coupled to each other to transmit electric signals therethrough. In particular, if electric signals could not be transmitted through male and female connectors in an electric connector employed in a safety device, because of imperfect coupling between the male and female connectors, the safety device would be unable to operate accurately. In order to avoid such a problem, an electric connector is generally designed to include a detection terminal for detecting whether male and female connectors are electrically connected to each other.
FIG. 24 is a perspective view of the electric connector disclosed in Japanese Patent Application Publication No. H8 (1996)-190961, and FIG. 25 is a cross-sectional view of the same.
The electric connector illustrated in FIGS. 24 and 25 includes a first connector housing 1 including a contact terminal 3, and a second connector housing 2 including a pair of terminals 9 and 9′. The contact terminal 3 and the terminals 9 and 9′ define a unit for detecting whether the first and second connector housing 1 and 2 are surely coupled to each other. The contact terminal 3 includes a pair of resilient pieces 3c facing each other, and a pair of resilient pieces 3c′ facing each other. When the first and second connector housings 1 and 2 are coupled to each other, the resilient pieces 3c sandwich the terminals 9 and 9′ therebetween, and similarly, the resilient pieces 3c′ sandwich the terminals 9 and 9′ therebetween. The first connector housing 1 is formed on an upper surface of the first connector housing 1 with a cantilever-type flexible lock arm 6 having a proximal end 6a. The lock arm 6 centrally includes an upwardly protruding protrusion 6b, and further includes a push-button portion 6c (see FIG. 25) at a free end thereof. When the lock arm 6 is compressed, the contact terminal 3 upwardly and downwardly resiliently moves.
In the conventional electric connector illustrated in FIGS. 24 and 25, the terminals 9 and 9′ slide with the resilient pieces 3c and 3c′ when the first and second connector housings 1 and 2 are coupled to each other, ensuring that even if the terminals 9 and 9′ are contaminated or corroded, such contamination or corrosion can be removed or wiped by virtue of the frictional force generated by the slide movement of the terminals 9 and 9′ relative to the resilient pieces 3c and 3c′. However, if a resistance against the slide movement of the terminals 9 and 9′ relative to the resilient pieces 3c and 3c′ were increased, the terminals 9 and 9′ would be engaged with the resilient pieces 3c and 3c′ when the lock arm 6 is inclining (see FIG. 25) before the lock arm 6 returns back to its original position (see FIG. 24), resulting in that the above-mentioned contamination or corrosion might be imperfectly wiped, and furthermore, the lock arm 6 might not be able to return back to its original position, resulting in that the first and second connector housings 1 and 2 are incompletely coupled to each other.
If the terminals 9 and the resilient pieces 3c and 3c′ are electrically connected to each other, even if the first and second connector housings 1 and 2 are incompletely coupled to each other, it is difficult to find the first and second connector housings 1 and 2 incompletely coupled to each other. If the first and second connector housings 1 and 2 are pulled in a direction away from each other due to impact and/or oscillation when the first and second connector housings 1 and 2 are incompletely coupled to each other, the first and second connector housings 1 and 2 may be pulled out of each other. If so, since signal lines connected by the first and second connector housings 1 and 2 are cut, a safety unit cannot operate even in an emergency.